| 摘要 |
PURPOSE:To obtain an input coupler for a carbon dioxide gas laser light hollow waveguide in which power capacity can be largely increased by providing an iris type exciting waveguide between a focusing lens for receiving a laser and the hollow waveguide. CONSTITUTION:A laser output light 1 from a carbon dioxide gas laser is focused by a lens 2, and introduced into a hollow waveguide 3 through an iris type exciting waveguide 6. The inner diameter 2a of a circular opening 7 n the iris type exciting waveguide 6 is so selected as to satisfy the following relationship, where z is a distance from the incident end of the hollow waveguide 3, a formula a<2>=ao<2>{1+[lambdaz/pir<2>ao<2>]} where lambda is oscillation wavelength of the carbon dioxide gas laser light, and r is a value in a range of 0.4-0.6. When a distance between the openings 7 of an iris is d, the value of d is determined when the Fresnel number N of the opening 7=a<2>/(lambdad) is 5 or more. As a result, it operates to convert the gauss type beam distribution by efficiently removing only the reverse phase of the amplitude distribution of the incident beam to reduce the quantity of generated heat near the incident end, and since the heat generation is distribution, an increase in the power capacity can be expected. |
